Distributed Interactive Media

With the rapid development of network and multimedia technologies, multimedia technologies like videophones and IP phones are widely used in everyday life, which in turn has increased the users' requirements for interactive media. Distributed interactive media, characterized by the direct interaction of users with the medium itself, has become an important research area of computer science. Distributed interactive media have wide applications in distance education, distributed virtual environment and network games etc. This paper studies several key technologies of distributed interactive media, including consistency control model, transportation of interactive media, application control model and interactive media security etc. It commences with the features of distributed interactive media; followed by a study of consistency control model, comprised of local lag model, local media state repair mechanism and state request method to guarantee the media consistency. After an analysis of different network protocols, this paper discusses the utilization of RTP/I protocol as the transport payload of interactive media. A new application control model - a combined model that combines with IP unicast and multicast technologies is proposed. The emulation experiments show that this model can alleviate the server's payload and improve the scalability as well. The security of interactive media is also discussed, including the multicast security architecture based on key trees and batch periodic rekeying methods. After the proposition of the design and application models of the shared whiteboard - one kind of distributed interactive media, the paper concludes with the realization of shared whiteboard payload and important algorithms.